Bought the air law cd from OAT, I was unconscious in 5 minutes! It is so slow and monotonous. Sold it on ebay the next day. Maybe I'm the wrong generation.
Used the ppl Pratt books & the simplifier. If you know the book inside out you can potentially get 100% -it is all in there, fairly easy to read & light hearted. Bought all mine on fleabay for next to nothing.
Good luck! Enjoy learning something new, even when entrenched in the full hideousness of air law .....